This international conference is Networks 2014 16th International Telecommunications Network Strategy and Planning Symposium at Portugal. The author present analysis evaluation of multiplex transmission using multiple input multiple output (MIMO) transmission and aggregate medium access control (MAC) protocol data unit (A-MPDU) for a collision detection scheme in wireless local area network (WLAN). In this presentation, we evaluate and analyze a proposed scheme for collision detection in WLANs by theoretical analysis and computer simulations. The proposed scheme utilizes the MAC procedure of MIMO transmission technology, which has been used to achieve transmission with a high link rate in WLANs in recent years; however, the transmission efficiency degrades at the MAC data service access point (SAP), although a high transmission link rate is achieved at the physical (PHY) layer. The transmission efficiency achieved by the proposed scheme is confirmed at a high level of approximately 97% when used with an A-MPDU by theoretical analysis and computer simulations, which is better than that of Ethernet. An A-MPDU has the effect of improving the transmission efficiency because it achieves a burst transmission of data packets. Furthermore, the results of our theoretical calculations correspond with the computer simulation results, indicating that the proposed scheme is indeed efficient and reliable.